Some conventional starting devices are situated and switched in parallel to start an internal combustion engine. Such an internal combustion engine usually has very large dimensions and a displacement of several 10's or 100's of liters.
In response to the use of parallel starting devices on one internal combustion engine, the simultaneous switching of the main current of the participating starter motors is important, since the simultaneous switching of the individual starter motors protects against overloading. In order to achieve this response which protects against overloading, the functions of engaging and switching are each implemented by a single relay. These two functions that are usually unified, that are carried out by an engaging relay, such as engaging a starter pinion and the switching on of the current for the starter motor are thus divided up. By separating the two functions, it is possible to provide an electrical circuit configuration in such a way that the starting device switches in the main current for the starter motor only when all engaging processes in all starting devices have been carried out. In this context, the engaging processes may have different engaging times, since the tooth-on-tooth position of a starter pinion in the ring gear requires a longer engaging process than a tooth-gap setting. In order to compensate for the time difference of at least two closing processes, the main current for the at least two starter motors is released simultaneously only when all closing processes have been carried out. Thus, for the engaging, succeeding relays are switched and closed one after another. An ignition current path is controlled in a control relay which releases an engaging relay. When there is current in all engaging relays, at least one switching relay is switched through which releases the main current for each starter motor. Switching off the starters takes place in the same sequence. The supplying of current to the control relay, then the engaging relay and last the switching relay is interrupted, so that the appropriate current paths are opened.
German Patent Application No. DE 10 2005 006 248 A1 describes a starting system for starting an internal combustion engine having several starters connected in parallel. In order to improve the switching certainty using the lowest possible wiring effort, the concatenation of the function “engaging” and “switching main current”, which is implemented by a relay, is divided to two relays, each having a separate function in each individual starter.
It is an object of the present invention further to develop a circuit configuration in such a way that at least one starter for starting an internal combustion engine works more exactly, and consequently achieves a longer service life.